Chemopreventive agents on a mouse skin carcinogenesis model: an integrative review / Agentes quimiopreventivos em um modelo de carcinogênese de pele em camundongos: uma revisão integrativa / Agentes quimiopreventivos en un modelo de carcinogénesis cutánea en ratón: una revisión integradora

Squamous cell carcinoma (SCC) is a non-melanoma skin cancer, with chronic sun exposure as the main risk factor. Excisional surgery is the most indicated treatment; however, patients can suffer functional, aesthetic, and psychological damage depending on the lesion site. Topical administration of 7,12-dimethylbenz[a]anthracene (DMBA) and 12-O-Tetradecanoylphorbol-13- acetate (TPA) induce to the appearance of benign skin tumors in mice, some of which develop into SCC. This protocol has been used to analyze the effects of many chemopreventive agents that may block or inhibit the mechanisms of action of chemical carcinogenesis. We compared the effects of chemopreventive agents in an induced skin carcinogenesis animal model. In the Scopus, PubMed, and EMBASE databases, we searched for manuscripts published between June 16, 2011, and June 16, 2021. We excluded studies conducted in vitro or on transgenic mice; in addition, studies without drug dosage, route of administration, or tumor incidence were excluded. We selected 26 studies and analyzed their main characteristics and the outcomes of tumorigenesis analysis. Most chemopreventive agents have shown excellent potential to inhibit the development of skin tumors. This review also discusses the standardization of studies in animal models to ensure better responses and future randomized clinical trials for cancer treatment and prevention.

O carcinoma espinocelular cutâneo (CEC) é um câncer de pele não melanoma, com a exposição solar crônica como o principal fator de risco. A cirurgia excisional é o tratamento mais indicado; entretanto, os pacientes podem sofrer danos funcionais, estéticos e psicológicos dependendo do local da lesão. A administração tópica de 7,12-dimetilbenz[a]antraceno (DMBA) e 12-O- Tetradecanoilforbol-13-acetato (TPA) induz ao aparecimento de tumores cutâneos benignos em camundongos, alguns dos quais evoluíram para CEC. Este protocolo tem sido utilizado para analisar os efeitos de muitos agentes quimiopreventivos que podem bloquear ou inibir os mecanismos de ação da carcinogênese química. Comparamos os efeitos de agentes quimiopreventivos em um modelo animal que foi induzido à carcinogênese de pele. Nas bases de dados Scopus, PubMed e EMBASE, buscamos manuscritos publicados entre 16 de junho de 2011 e 16 de junho de 2021. Excluímos estudos realizados in vitro ou em camundongos transgênicos; além disso, estudos sem dosagem de drogas, via de administração ou incidência de tumores foram excluídos. Selecionamos 26 estudos e analisamos suas principais características e os resultados da análise da tumorigênese. A maioria dos agentes quimiopreventivos tem demonstrado excelente potencial para inibir o desenvolvimento de tumores cutâneos. Esta revisão também discute a padronização de estudos em modelos animais para garantir melhores respostas e futuros ensaios clínicos randomizados para tratamento e prevenção do câncer.

El carcinoma de células escamosas (CCE) es un cáncer de piel no melanoma, cuyo principal factor de riesgo es la exposición crónica al sol. La cirugía de escisión es el tratamiento más indicado; sin embargo, los pacientes pueden sufrir daños funcionales, estéticos y psicológicos dependiendo de la localización de la lesión. La administración tópica de 7,12-dimetilbenz[a]antraceno (DMBA) y 12-O-Tetradecanoilforbol-13-acetato (TPA) inducen a la aparición de tumores cutáneos benignos en ratones, algunos de los cuales se convierten en CCE. Este protocolo se ha utilizado para analizar los efectos de muchos agentes quimiopreventivos que pueden bloquear o inhibir los mecanismos de acción de la carcinogénesis química. Comparamos los efectos de los agentes quimiopreventivos en un modelo animal de carcinogénesis cutánea inducida. En las bases de datos Scopus, PubMed y EMBASE, se buscaron los manuscritos publicados entre el 16 de junio de 2011 y el 16 de junio de 2021. Se excluyeron los estudios realizados in vitro o en ratones transgénicos; además, se excluyeron los estudios sin dosis de fármacos, vía de administración o incidencia tumoral. Se seleccionaron 26 estudios y se analizaron sus características principales y los resultados del análisis de la tumorigénesis. La mayoría de los agentes quimiopreventivos han mostrado un excelente potencial para inhibir el desarrollo de tumores cutáneos. Esta revisión también analiza la estandarización de los estudios en modelos animales para garantizar mejores respuestas y futuros ensayos clínicos aleatorios para el tratamiento y la prevención del cáncer.

Curcumin Nanoemulsions Stabilized with Modified Phosphatidylcholine on Skin Carcinogenesis Protocol.

BACKGROUND: Cancer is one of the main causes of death by disease; several alternative treatments have been developed to counteract this condition. Curcumin (diferuloylmethane), extracted from the rhizome of Curcuma longa, has antioxidant, anti-inflammatory, and anti-cancer properties; however, it has low water solubility and poor intestinal absorption. Carrier systems, such as nanoemulsions, can increase the bioavailability of lipophilic bioactive compounds. OBJECTIVE: To evaluate the effect of curcumin nanoemulsions prepared with lecithin modified with medium-chain fatty acids as an emulsifier, on the expression of the Cdk4, Ccne2, Casp8 and Cldn4 genes involved in the carcinogenesis process in K14E6 transgenic mice. METHODS: The emulsifier was prepared by interesterification of medium-chain fatty acids, pure lecithin, and immobilized phospholipase-1 on Duolite A568. An Ultraturrax homogenizer and a Branson Ultrasonic processor were used for the preparation of nano-emulsions, and a Zetasizer evaluated the particle size. qRT-PCR analysis was performed to quantify the cancer-related genes expressed in the K14E6 mice. The development and evolution of skin carcinogenesis were assessed through histological analysis to compare cell morphology. RESULTS: Ca 59% of the MCFA were incorporated via esterification into the PC within 12 hours of the reaction. An emulsifier yield used to formulate the NE of 86% was achieved. Nanoemulsions with a particle size of 44 nm were obtained. The curcumin nano-emulsion group had a 91.81% decrease in the tumorigenesis index and a reduction in tumor area of 89.95% compared to the sick group. Histological analysis showed that the group administered with free curcumin developed a microinvasive squamous cell carcinoma, as opposed to the group with nanoemulsion which presented only a slight inflammation. In gene expression, only a significant difference in Cdk4 was observed in the nanoemulsion group.

Effect of Sodium Arsenite on Mouse Skin Carcinogenesis.

Arsenic is carcinogenic in human beings, and environmental exposure to arsenic is a public health issue that affects large populations worldwide. Thus, studies are needed to determine the mode of action of arsenic and prevent harmful effects arising from arsenic intake. The present study assessed the influence of sodium arsenite (As(3+)) on potentially carcinogenic processes that are either pre-existing or concomitant with chronic intake of water containing As(3+). Experiments using SenCar mice were designed to evaluate the effect of chronic administration of As(3+) (2, 20, or 200 mg of As(3+)/L) in drinking water that overlapped to varying degrees with a 2-stage carcinogenesis protocol carried out over 9 months. The results showed a time-dependent pattern. During early stages of carcinogenesis (6-12 weeks), animals exposed to As(3+) and the carcinogenesis protocol showed increased numbers of tumors compared to control animals. During late carcinogenesis (16-30 weeks), the number of tumors stabilized to below control values, but the tumors showed increased malignancy. These findings indicate that the outcomes of the 2-stage skin carcinogenesis protocol are modified by the presence of arsenite in drinking water, which increases the rate of carcinoma development.